课程设计机械带式运输机设计

带式运输机设计第一章 任务书21.1课程设计说明21.2课程设计任务书31.2.1运动简图31.2.2原始数据31.2.3已知条件31.2.4设计工作量：4第二章 减速器设计步骤52.1电动机的选择52.1.1选择电动机的类型52.1.2选择电动机的容量52.1.3确定电动机转速62.2确定传动装置的总传动比和分配传动比72.2.1分配减速器的各级传动比72.2.2计算各轴的动力和动力参数72.3传动零件的设计计算82.3.1 V带设计82.3.2齿轮设计：102.4减速器结构设计172.5轴的设计及效核182.5.1初步估算轴的直径182.5.2联轴器的选取192.5.3初选轴承192.5.4轴的结构设计（直径，长度来历）192.5.5低速轴的校核212.6轴承的寿命计算232.7键连接的选择和计算252.8减数器的润滑方式和密封类型的选择252.8.1齿轮传动的润滑252.8.2润滑油牌号选择262.8.3密封形式262.9设计总结27致谢27参考资料27第一章 任务书1.1课程设计说明本次设计为课程设计，通过设计单级级齿轮减速器，学习机械设计的基本过程、步骤，规范、学习和掌握设计方法，以学习的各种机械设计，材料，运动，力学知识为基础，以机械设计、机械原理、机械制图、机械设计课程设计手册、制造技术基础、机械设计课程设计指导书以及各种国标为依据，独立自主的完成单级级减速器的设计、计算、验证的全过程。亲身了解设计过程中遇到的种种问题和解决的方法，思考、分析最优方案，这是一次独立自主的设计过程，为毕业设计及以后的就业工作做下铺垫。1.2课程设计任务书课程设计题目1：带式运输机1.2.1运动简图 1.22原始数据题 号参 数12345678910运输带工作拉力F（KN）3.03.03.02.82.62.52.42.22.01.8运输带工作速度v（m/s）2.01.81.61.91.91.91.81.71.61.5滚筒直径D（mm）400450400400400450450450450450每日工作时数T（h）16161616161616161616使用折旧期（y）88888888881.2.3已知条件1、工作情况：传动不逆转，载荷平稳，允许运输带速度误差为5%；2、滚筒效率：j=0.96（包括滚筒与轴承的效率损失）；3、工作环境：室内，灰尘较大，最高环境温度35C；4、动力来源：电力，三相交流，电压380/220V；5、检修间隔期：四年一次大修，两年一次中修，半年一次小修；6、制造条件及生产批量：一般机械厂生产制造，小批量。1.2.4设计工作量：1、减速器装配图1张（A0或A1）；2、零件工作图13张；3、设计说明书1份。第二章 减速器设计步骤2.1电动机的选择2.1.1选择电动机的类型按工作要求和条件，选用三机笼型电动机，封闭式结构，电压380V，Y型。2.1.2选择电动机的容量 （2-1） （其中：为电动机功率，为负载功率，为总效率。） 由电动机到传输带的传动总效率为 图2-1 运动简图式中：、 分别为带传动、轴承、 齿轮传动、联轴器和卷筒的传动效率。取（带传动），（球轴承），（直齿轮），（弹性联轴器），（已知）。所以因载荷平稳，电动机额定功率只需要稍大于即可，按表2.1中Y系列的电动机数据，选电动机的额定功率7.5kw表2.1 各种电机参数电机型号额定功率/(kw)满载转速/(r/min)堵转转矩额定转矩最大转矩额定转矩重量/(kg)同步转速3000r/min,2极Y801-20.7528252.22.317Y802-21.128252.22.318Y90S-21.528402.22.320Y90L-22.228402.22.324Y100L-2328802.22.336Y112M-2428902.22.346Y132S2-25.5290022.364Y132S2-27.5290022.370Y160M1-211293022.3117同步转速1500r/min,4极Y801-40.5513902.22.417Y802-40.7513902.32.318Y90S-41.114002.32.321Y90L-41.514002.32.325Y100L1-42.214202.22.336Y100L2-4314202.22.340Y112M-4414402.22.350Y132S-45.514402.22.365Y132M-47.514402.22.381Y160M-41114602.22.3122同步转速1000r/min,6极Y90S-60.7591022.221Y90L-61.191022.224Y100L-61.594022.235Y112M-62.294022.245Y132S-6396022.262Y132M1-6496022.271Y132M2-65.596022.280Y160M-67.597022119Y160L-61197022140同步转速750r/min,8极Y132S-82.27102262Y132M-837102272Y160M1-8472022105Y160M2-85.572022116Y160L-87.572022145Y180L-8117301.721842.1.3确定电动机转速卷筒转速为=90按推荐的传动比合理范围，取V带传动的传动比,一级圆柱齿轮减速器的传动比为，则从电动机到卷筒轴的总传动比合理范围为。故电动机转速的可选范围为 可见，电动机同步转速可选、和两种。根据相同容量的两种转速，从表2-1中查出两个电动机型号，再将总传动比合理分配给V带和减速器，就得到两种传动比方案，如表2-2所示。表2-2 两种不同的传动比方案方案电动机型号额定功率 kw电动机转速电动机重量Kg传动装置的传动比同步转速满载转速总传动比V带减速器1Y160L-87.57507201458.002.004.002Y132S2-27.5300029007032.222.8011.51 综合考虑电动机和传动装置的尺寸、重量和带传动、减速器的传动比，选择第1种方案，即电动机型号为Y160L-8。电动机中心高H =160mm,外伸轴段DE=42110mm。2.2确定传动装置的总传动比和分配传动比2.2.1分配减速器的各级传动比 由选定的电动机满载转速和工作机主动轴转速n，可得传动装置总传动比为 =/n总传动比为各级传动比,的乘积，即具体取值见上表2-2方案一2.2.2计算各轴的动力和动力参数（1）计算各轴转速 轴 =360 轴 =90 卷通轴 =90 （2）计算各轴输入功率、输出功率 轴 =6.410.96=6.15366.15 kw 轴 =6.15360.980.97=5.849612165.85 kw卷筒轴=5.849612160.980.97=5.5606413192965.56kw各轴的输出功率为输入功率乘轴承效率0.98，分别为轴 =6.150.98=6.0276.03 kw轴 =5.850.98=5.7335.73 kw卷筒轴=5.560.98=5.44885.45kw（3）计算各轴的输入、输出转矩。电动机轴输出转矩 轴输入转矩 轴输入转矩 卷筒机输入转矩各轴的输出转矩分别为各轴的输入转矩乘轴承效率0.98表2-3 运动和动力参数计算结果轴名功率 P/KW转矩T/N*M转速nr/min转动比i效率输入输出输入输出电机6.4185.027202.000.98轴6.156.03163.15159.89360轴5.855.73620.75608.34904.000.95卷筒轴5.565.45589.98578.18901.000.952.3传动零件的设计计算2.3.1 V带设计（1）、已知条件和设计内容 设计V带传动时的已知条件包括：带传动的工件条件；传动位置与总体尺寸限制；所需传递的额定功率P；小带轮转速；大带轮（2）、设计步骤：1）、确定计算功率 根据工作条件载荷平稳，由机械设计基础教材（以下简称教材）表12-6查得=1.2，计算功率为 2）、选择V带的带型根据计算功率 ,小带轮的转速，由教材图12-14选用A型带。3）、确定带轮的基准直径，并验算带速v初选小带轮基准直径 根据v带的带型，由表12-3和图12-14，取小带轮的基准直径=140mm。 验算带速 v 由于5 m/s v 25 m/s ，故带速合适。4）、计算大带轮的基准直径由,传动比,有 =2.00140=280mm，根据表12-7，取=280 mm5）确定V带的中心距 ,并选V带的基准长度确定小带轮中心距根据式12-16 0.7(+)=2942(+)=840初定中心距=500mm。 计算相应的带长 由教材表12-2选带的基准长度=1600 mm 计算实际中心距a及其变动范围 中心距的变化范围为6）、验算小带轮上的包角 包角合适。7）、计算带的根数计算单根V带的额定计算功率，由 和，查教材表12-3得P0=1.41kw查教材表12-4得查教材表12-6得，查教材表12-5得，取5根。8）确定带的最小初拉力由教材表12-1得A型带的单位长度质量 q=0.10 kg/m,9)计算带传动的压轴力Fp 压轴力的最小值为(3) 把带传动的设计计算结果记入表2-4中表2-4 带传动的设计参数 带型V中心距465.4小带轮直径140包角162.76大带轮直径280带长1600带的根数5初拉力160.57带速5.28压轴力1587.562.3.2齿轮设计：一、齿轮传动计算已知条件：输入功率=6.15kw,小齿轮转速传动比 =4,工作寿命为8年（年工作日250天），两班制。(1)选定齿轮类型、材料和齿数1）选用斜齿圆柱齿轮传动2）材料选择。由教材表10-1选择小齿轮材料为40Cr(调质)，硬度为280HBS,大齿轮材料为45钢（调质），硬度为240HBS，二者材料硬度差为40HBS。3）选择小齿轮齿数=32，大齿轮齿数=432=128。(2)按齿面接触强度设计由机械设计第六章(课件)齿轮公式（6.14）知齿面接触强度设计公式为1)确定上公式内的各计算数值计算载荷系数K由1表6.2查得使用系数=1，由1134页得=1, 。由1公式（6.2）得载荷系数 K= =111.1=1.1计算小齿轮传递的转矩=9.55=9.55=1.6315Nmm由1表6.8选取齿宽系数=1。由1图6.14按齿面硬度查得小齿轮的接触疲劳极限=700 MPa;大齿轮的接触疲劳强度极限=550 MPa。计算应力循环次数 =60j=603601(162508)=6.912108 =1.728108由1图6.6取接触疲劳寿命系数=1；=1.2计算接触疲劳许用应力 由1表6.5，取失效概率为1%，安全系数S=1，则 =1700=700 MPa =1.2550=660 MPa查1中：图6.12,得节点区域系数=2.433。参考1中143页,取Z=0.86；Z=1；由表6.3查得材料的弹性影响系数=189.8 MPa。4许用接触应力= 660 MPa2）计算试算小齿轮分度圆直径d1,由计算公式得 26 mm计算齿轮模数mn=1.3mm；查手册取标准模数mn=2mm计算齿轮几何参数 mmd2=id1=464=256 mm中心距： mm齿轮宽度：因为b=d=164=64 mm，故取b1=65mm；b2=60mm计算圆周速度，确定齿轮精度V=1.21 m/s参考1中图6.18（a），取齿轮精度8级。 (3)按齿根弯曲强度校核由1公式（6.15）知弯曲强度校核公式为 1)确定校核公式中的计算参数载荷系数（前面已经得到） K= =111.1=1.1 参考5中73页图8-9查得Y=1.62, Y=1.81图8-10取重合度系数Y=0.69计算当量齿数 =32 =128查5中表8-8查得得取齿形系数 =2.53, =2.22查5中73页图8-9得取应力校正系数 =1.62, =1.81计算弯曲疲劳许用应力查5中图8-11得小齿轮的弯曲疲劳强度极限Flim1=220MPa;大齿轮的弯曲疲劳强度极限Flim2=170MP查5中图8-11取弯曲疲劳寿命系数YN1= YN2=1，查5中表8-20取弯曲疲劳安全系数S=1.25则1=176 MPa2=136 MPa2）校核计算=13.2170 MPa12.9577 MPa因， 故弯曲强度足够。二、圆柱齿轮传动参数表各级大齿轮、小齿轮几何尺寸和参数的计算结果如下表 表2-5 圆柱齿轮传动参数表名称代号单位高速级小齿轮大齿轮中心距amm160传动比i4模数mnmm2端面压力角20啮合角20齿数z32128分度圆直径dmm64256节圆直径dmm64256齿顶圆直径damm68260齿根圆直径dfmm59251齿宽bmm6560材料4545热处理状态调质调质齿面硬度HBS280240正常齿：h=1 C=0.252.4减速器结构设计 表2-6 减速箱机体结构尺寸名称符号减速器型式及尺寸关系/mm机座壁厚 8机盖壁厚8机座凸缘厚度12机盖凸缘厚度12机座底凸缘厚度20地脚螺钉直径20地脚螺钉数目4轴承旁联接螺栓直径16机盖与座联接螺栓直径12联接螺栓的间距180轴承端盖螺栓直径10窥视孔盖螺钉直径7定位销直径16、到外箱壁距离26、22 、18、至凸缘边缘距离24、16轴承旁凸台半径C凸台高度由结构确定外箱壁至轴承座端面距离40大齿轮顶圆与内箱壁距离10齿轮端面与内箱壁距离10箱盖、箱座肋厚、7、7轴承端盖外径130、112轴承端盖凸缘厚度10轴承旁联接螺栓距离1452.5轴的设计及校核2.5.1初步估算轴的直径在进行轴的结构设计之前，应首先初步计算轴的直径。一般按受扭作用下的扭转强度估算各轴的直径，计算公式为，式中：P轴所传递的功率，kw； n轴的转速，r/min;A由轴的需用切应力所确定的系数。由于减速器传递的功率不大，对其重量和尺寸也无特殊要求，故选择常用材料45钢，调质处理，查教材表13-2得A=107118，则 I 轴 =28.3 mm 轴=44.23 mm 将各轴圆整为=30mm , =45 mm。2.5.2联轴器的选取 轴I段需要与联轴器连接，为使该段直径与联轴器的孔径相适应，所以需要同时选用联轴器，又由于本减速器属于中小型减速器，其输出轴与工作机的轴线偏移不大。其次为了能够使传送平稳，所以必须使传送装置具有缓冲，吸振的特性。因此选用弹性套柱销联轴器,由1表10.11查得：工作情况系数=1.5,由6表8-5查得：选用LT8型弹性套柱销联轴器，其主要参数为：公称转矩Tn=710Nm轴孔长度112mm(Y型)孔径=45mm表2-7联轴器外形及安装尺寸型号公称扭矩Nm许用转速r/min轴孔直径mm轴孔长度mmDmm转动惯量kgm2许用补偿量轴向径向角向LT87103000451122240.1341.50.4102.5.3初选轴承I 轴选轴承为：6007； 轴选轴承为：6010；所选轴承的主要参数如表2-8 表2-8 轴承的型号及尺寸轴承代号基本尺寸/mm安装尺寸/mm基本额定/kNdDBdnDa动载荷Cr静载荷Cor6007356214415616.210.5601050801656742216.22.5.4轴的结构设计（直径，长度来历）一 低速轴的结构图 图2-2 低速轴结构简图根据轴向定位可靠要求，确定轴的各段直径和长度（1）I段与联轴器配合 =45,为了保证轴端挡圈只压在半联轴器上而不压在轴的端面上取=110。（2）为了满足半联轴器的轴向定位，段右侧设计定位轴肩，由表7-123毡圈油封的轴颈取=48mm,由轴从轴承孔端面伸出15-20mm,由结构定取=45mm。(3）轴肩为非定位轴肩初选深沟球轴承，取=50mm考虑轴承定位稳定，略小于轴承宽度加挡油环长度，取=36mm。(4)轴上安装齿轮的定位要求及箱体之间关系尺寸，取=53mm, =58mm。(5)轴肩V为定位轴肩，直径应大于安装于轴上齿轮内径6-10mm,且保证10mm ,取= 60mm，=8mm。（6）VI 段，取=56 mm,考虑轴承轴安装和定位。取=10mm图2-3 高速轴结构简图(7)VII 右端为砂轮越程槽，=45mm , =3mm(8)轴肩V间安装深沟球轴承6010, 取=50mm，根据箱体结构 取=14(9）低速轴上齿轮、半联轴器零件的轴向定位均采用平键连接。由表4-16查得齿轮与轴用平键lbh=451610（GB1095-2003）,键槽用键槽铣刀加工，长为63mm。同样半联轴器与轴的联接，选用平键bh=149，键长选择97。轴端倒角1.545，各轴肩处圆角半径R=1.6mm。(10)高速轴类似,分别lbh=50128 V带键槽为lbh=4587 二、高速轴结构图高速轴结构确定与低速轴相似并协调好两轴跨距等问题,最终确定如图2-3所示.(轴的具体确定也可参见如下PPT.) 2.5.5轴的校核由于低速轴上所承受的转矩最大，所以仅对低速轴按弯扭合成强度条件进行校核计算。（1） 轴强度的校核计算1）低速轴计算图如图2-4，按垂直面且去轴承中心为受力点进行校核。将轴简化为如下简图 图2-4低速轴轴的计算简图（2）弯矩图根据上述简图，按垂直面计算各力产生的弯矩，做出垂直面上的弯矩图（图2-5）。已知=620.75, =589.95Nm，齿轮分度圆直径d=256mm,对于6010型轴承，取轴承中心为受力点,得到做为简支梁的轴的支撑跨距L+L=57+58=115mm4849.61N1765.11N 在水平面上为 在垂直平面上为=在水平面上，齿轮所在轴截面为在垂直平面上，齿轮所在轴截面为合成弯矩，齿轮所在轴截面为从轴的结构以及扭矩图中可以看出截面C是危险截面，现将计算出的截面C处的弯矩值列下表 表2-9 截面C弯矩值数据表载荷水平面H垂直面V支反力F=4849.61N =1765.11N弯矩总弯矩扭矩TT=620.75Nmm（3）扭矩图 图2-5 轴的载荷分析图（4）校核轴的强度 因齿轮所在轴截面弯矩大，同时截面还作用有转矩，因此此截面为危险截面。其抗弯截面系数为抗扭截面系数为弯曲应力为扭剪应力为按弯扭合成强度进行校核计算，对于单向转动的轴，转矩按脉动循环处理，故取折合系数，则当量应力为由5表8-26查得45刚调质处理抗拉强度极限，由表8-32用插值法查得轴的许用弯曲应力，强度满足要求2.6轴承的寿命计算（1）低速轴轴承寿命计算1）预期寿命从减速器的使用寿命期限考虑，轴承使用期限为8年（年工作日为250天）。预期寿命=825016=32000h=3.2h2）寿命验算轴承所受的载荷 =4849.61N =1765.11N由表8-28查得6010轴承得，,因轴承不受轴向力，轴承A、B当量动载荷为.验算轴承寿命查表14-74得到=1.2已知，温度系数=1（常温）图2-6 轴承的受力简图所以所选轴承可满足寿命要求。2.7键连接的选择和计算（1）低速轴齿轮的键联接1） 选择类型及尺寸 根据d=53mm,L=58mm,选用A型，bh=1610,L=50mm2）键的强度校核键的工作长度l及键与轮毂键槽的接触高度kl=L-b=50-16=34mmk=0.5h=5mm强度校核大齿轮处键连接的挤压应力为，取知键、轴及齿轮的材料都为刚，由5表8-33查得，强度足够 ,键安全合格.（2）低速轴联轴器的键联接1）选择类型及尺寸 根据d=45mm,L=110mm,选用C型，bh=149,L=97mm2）键的强度校核r键的工作长度l及键与轮毂键槽的接触高度kl=L-b/2=97-7=90mmk=0.5h=5mm强度校核此处，键、轴和轮毂的材料都是钢，620.75Nmm键安全合格2.8减数器的润滑方式和密封类型的选择2.8.1齿轮传动的润滑本设计采用油润滑。润滑方式为飞溅润滑，并通过适当的油沟来把油引入各个轴承中。1）齿轮的润滑采用浸油润滑，浸油高度为30-50mm。另外传动件浸油中深度要求适当，要避免搅油损失太大，又要充分润滑。油池应保持一定的深度和储油量。2）滚动轴承的润滑滚动轴承宜开设油沟、飞溅润滑。2.8.2润滑油牌号选择由表7.13得：闭式齿轮传动润滑油运动粘度为220mm/s。选用L-CKC220润滑油。2.8.3密封形式用凸缘式端盖易于调整，采用闷盖安装骨架式旋转轴唇形密封圈实现密封。轴与轴承盖之间用接触式毡圈密封，型号根据轴段选取。2.9设计总结通过本次一级减速器的设计，让我对机械行业中产品的设计过程有了亲身体会，同时体会到机械设计的过程是严谨的分工步骤，开放的设计思想，细致的计算验证，反复推导的过程，任何一个环节都不能疏漏，借鉴前人的经验技巧，参阅各种标准手册，站在全局来设计产品。通过本次设计过程，我更认识了自己的不足，一个产品的设计需要方方面面的知识，经验，技巧作为基础，这也是我的执着追求。致谢非常感谢陈老师在课程设计过程中对我的指导，也感谢在设计过程中所有给过我帮助和讲解的同学，非常感谢你们！ 参考资料参考文献1 杨明忠、朱家诚主编.机械设计M.武汉理工大学出版社，20061-284.2 濮良贵、纪名刚主编.机械设计.8版.高等教育出版社，2006.5；22-4083龚溎义主编 机械设计课程设计指导书 第二版高等教育出版社1989;4岳大鑫、王忠主编机械设计基础 西安电子科技大学出版社2007.95张春宜 郝光平 刘敏编 减速器设计实例精讲 机械工业出版社 2010.16吴宗泽 罗胜国主编 机械设计课程设计手册（第3版）2006.4Employment tribunals sort out disagreements between employers and employees.You may need to make a claim to an employment tribunal if: you dont agree with the disciplinary action your employer has taken against you your employer dismisses you and you think that you have been dismissed unfairly.For more information about dismissal and unfair dismissal, seeDismissal.You can make a claim to an employment tribunal, even if you haventappealedagainst the disciplinary action your employer has taken against you. However, if you win your case, the tribunal may reduce any compensation awarded to you as a result of your failure to appeal.Remember that in most cases you must make an application to an employment tribunal within three months of the date when the event you are complaining about happened. If your application is received after this time limit, the tribunal will not usually accept it.If you are worried about how the time limits apply to you, take advice from one of the organisations listed underFurther help.Employment tribunals are less formal than some other courts, but it is still a legal process and you will need to give evidence under an oath or affirmation.Most people find making a claim to an employment tribunal challenging. If you are thinking about making a claim to an employment tribunal, you should get help straight away from one of the organisations listed underFurther help.If you are being represented by a solicitor at the tribunal, they may ask you to sign an agreement where you pay their fee out of your compensation if you win the case. This is known as adamages-based agreement. In England and Wales, your solicitor cant charge you more than 35% of your compensation if you win the case.If you are thinking about signing up for a damages-based agreement, you should make sure youre clear about the terms of the agreement. It might be best to get advice from an experienced adviser, for example, at a Citizens Advice Bureau. To find your nearest CAB, including those that give advice by e-mail, click onnearest CAB.For more information about making a claim to an employment tribunal, seeEmployment tribunals.The (lack of) air up there Watch mCayman Islands-based Webb, the head of Fifas anti-racism taskforce, is in London for the Football Associations 150th anniversary celebrations and will attend Citys Premier League match at Chelsea on Sunday.I am going to be at the match tomorrow and I have asked to meet Yaya Toure, he told BBC Sport.For me its about how he felt and I would like to speak to him first to find out what his experience was.Uefa hasopened disciplinary proceedings against CSKAfor the racist behaviour of their fans duringCitys 2-1 win.Michel Platini, president of European footballs governing body, has also ordered an immediate investigation into the referees actions.CSKA said they were surprised and disappointed by Toures complaint. In a statement the Russian side added: We found no racist insults from fans of CSKA.Age has reached the end of the beginning of a word. May be guilty in his seems to passing a lot of different life became the appearance of the same day; May be back in the past, to oneself the paranoid weird belief disillusionment, these days, my mind has been very messy, in my mind constantly. Always feel oneself should go to do something, or write something. Twenty years of life trajectory deeply shallow, suddenly feel something, do it.一字开头的年龄已经到了尾声。或许是愧疚于自己似乎把转瞬即逝的很多个不同的日子过成了同一天的样子；或许是追溯过去，对自己那些近乎偏执的怪异信念的醒悟，这些天以来，思绪一直很凌乱，在脑海中不断纠缠。总觉得自己自己似乎应该去做点什么，或者写点什么。二十年的人生轨迹深深浅浅，突然就感觉到有些事情，非做不可了。The end of our life, and can meet many things really do?而穷尽我们的一生，又能遇到多少事情是真正地非做不可？During my childhood, think lucky money and new clothes are necessary for New Year, but as the advance of the age, will be more and more found that those things are optional; Junior high school, thought to have a crush on just means that the real growth, but over the past three years later, his writing of alumni in peace, suddenly found that isnt really grow up, it seems is not so important; Then in high school, think dont want to give vent to out your inner voice can be in the high school children of the feelings in a period, but was eventually infarction when graduation party in the throat, later again stood on the pitch he has sweat profusely, looked at his thrown a basketball hoops, suddenly found himself has already cant remember his appearance.童年时，觉得压岁钱和新衣服是过年必备，但是随着年龄的推进，会越来越发现，那些东西根本就可有可无；初中时，以为要有一场暗恋才意味着真正的成长，但三年过去后，自己心平气和的写同学录的时候，突然就发现是不是真正的成长了，好像并没有那么重要了；然后到了高中，觉得非要吐露出自己的心声才能为高中生涯里的懵懂情愫划上一个句点，但毕业晚会的时候最终还是被梗塞在了咽喉，后来再次站在他曾经挥汗如雨的球场，看着他投过篮球的球框时，突然间发现自己已经想不起他的容颜。Originally, this world, can produce a chemical reaction to an event, in addition to resolutely, have to do, and time.原来，这个世界上，对某个事件能产生化学反应的，除了非做不可的坚决，还有，时间。A persons time, your ideas are always special to clear. Want, want, line is clear, as if nothing could shake his. Also once seemed to be determined to do something, but more often is he backed out at last. Dislike his cowardice, finally found that there are a lot of love, there are a lot of miss, like shadow really have been doomed. Those who do, just green years oneself give oneself an arm injection, or is a self-righteous spiritual.一个人的时候，自己的想法总是特别地清晰。想要的，不想要的，界限明确，好像没有什么可以撼动自己。也曾经好像已经下定了决心去做某件事，但更多的时候是最后又打起了退堂鼓。嫌恶过自己的怯懦，最终却发现有很多缘分，有很多错过，好像冥冥之中真的已经注定。那些曾经所谓的非做不可，只是青葱年华里自己给自己注射的一支强心剂，或者说，是自以为是的精神寄托罢了。At the moment, the sky is dark, the air is fresh factor after just rained. Suddenly thought of blue plaid shirt; Those were broken into various shapes of stationery; From the corner at the beginning of deep friendship; Have declared the end of the encounter that havent start planning. Those years, those days of do, finally, like youth, will end in our life.此刻，天空是阴暗的，空气里有着刚下过雨之后的清新因子。突然想到那件蓝格子衬衫；那些被折成各种各样形状的信纸；那段从街角深巷伊始的友谊；还有那场还没有开始就宣告了终结的邂逅计划那些年那些天的非做不可，终于和青春一样，都将在我们的人生中谢幕。Baumgartner the disappointing news: Mission aborted. r plays an important role in this mission. Starting at the ground, conditions have to be very calm - winds less than 2 mph, with no precipitation or humidity and limited cloud cover. The balloon, with capsule attached, will move through the lower level of the atmosphere (the troposphere) where our day-to-day weather lives. It will climb higher than the tip of Mount Everest (5.5 miles/8.85 kilometers), drifting even higher than the cruising altitude of commercial airliners (5.6 miles/9.17 kilometers) and into the stratosphere. As he crosses the boundary layer (called the tropopause),e can expect a lot of turbulence.The supersonic descent could happen as early as Sunda.The weatheThe balloon will slowly drift to the edge of space at 120,000 feet ( Then, I would assume, he will slowly step out onto something resembling an Olympic diving platform.Below, the Earth becomes the concrete bottom of a swimming pool that he wants to land on, but not too hard. Still, hell be traveling fast, so despite the distance, it will not be like diving into the deep end of a pool. It will be like he is diving into the shallow end. Skydiver preps for the big jumpWhen he jumps, he is expected to reach the speed of sound - 690 mph (1,110 kph) - in less than 40 seconds. Like hitting the top of the water, he will begin to slow as he approaches the more dense air closer to Earth. But this will not be enough to stop him completely.If he goes too fast or spins out of control, he has a stabilization parachute that can be deployed to slow him down. His team hopes its not needed. Instead, he plans to deploy his 270-square-foot (25-square-meter) main chute at an altitude of around 5,000 feet (1,524 meters).In order to deploy this chute successfully, he will have to slow to 172 mph (277 kph). He will have a reserve parachute that will open automatically if he loses consciousness at mach speeds.Even if everything goes as planned, it wont. Baumgartner still will free fall at a speed that would cause you and me to pass out, and no parachute is guaranteed to work higher than 25,000 feet (7,620 meters).cause there